title: Giant intraosseous schwannoma of the ileopubic ramus.
abstract: Schwannomas are the most common tumors of the peripheral nerves. Intraosseous schwannoma is a rare entity; approximately 200 cases are described in the world literature, with only 1 involving the ileopubic ramus. To the authors' knowledge, this article is the first to describe a giant intraosseous schwannoma of the ileopubic ramus, its clinical presentation and radiographic aspect, its histological findings, its biological behavior, and the differential diagnosis. It is also the first to describe surgical treatment of this entity. A 63-year-old woman presented with paroxysmal pain at the right groin. Radiographs showed a multilocular lytic lesion of the right ileopubic ramus, extending from the acetabulum to the pubic symphysis. Magnetic resonance imaging revealed extraosseous extension in the pelvis and in the anteromedial region of the right thigh. An incisional biopsy revealed fibroconnective tissue with sparse spindle cells in a myxoid stroma; diffuse expression of S100 protein was observed by immunohistochemistry. Intraosseous neurofibroma was the first histopathologic diagnosis. The 12×8×4-cm lesion was entirely removed via a Letournel ileoinguinal approach. Reconstruction of the ileopubic ramus was performed with an autologous bone graft taken from the omolateral iliac crest and fixed by a pelvic reconstruction plate. Histopathological examination revealed Antoni A and B patterns with Verocay bodies, no mitosis or cellular atypia, and diffuse expression of S100 protein by immunohistochemistry, all features indicative of a benign schwannoma. The patient returned to activities of daily living with no limitations. No recurrence had occurred 24 months postoperatively.
authors.affiliation: Clinica Ortopedica e Traumatologica, Università di Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Benazzo
authors.forename: Matteo
authors.initials: M
authors.lastname: Marullo
authors.forename: Stefano Marco Paolo
authors.initials: SM
authors.lastname: Rossi
authors.forename: Erika
authors.initials: E
authors.lastname: Viola
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D009442:Neurilemmoma / Q000175:diagnosis* / Q000601:surgery*; D011631:Pubic Symphysis / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D016896:Treatment Outcome